Conventional fundus cameras each have a single-lens reflex digital camera as its photographing unit. When a photographing switch on a joy stick of the fundus camera is pressed, the digital camera of the imaging unit captures an image of a target. In capturing an image, photographing conditions (e.g., ISO sensitivity and shutter speed) may be directly set using user interface switches of the digital camera (hereinafter, referred to as user interface (UI) switches), or set through an external personal computer (PC) in communication with the digital camera.
Japanese Patent Application Laid-Open No. 2003-216374 discusses a technology of printer driver that makes inaccessible commands available to users in its maintenance mode. Japanese Patent Application Laid-Open No. 11-119326 discusses a technology to provide a function to accept a password to a single-lens reflex digital camera such that an input of a password can cancel a state of the camera that prohibits photographing. In such digital cameras as imaging units of conventional fundus cameras, however, the UI switches are arranged on a face thereof. As a result, operation errors in pressing switches to change photographing conditions may occur, and operators may forget to restore settings for a new subject and thereby capture images in inappropriate photographing conditions. In other cases, another error may happen: even when photographing conditions are already set using an external PC, an operator, without knowing it, may change the photographing conditions using UI switches, and a next operator does not notice the change and capture images under the conditions as they are.
Digital cameras sensitive to infrared rays are sometimes used as photographing units of fundus cameras. These digital cameras can be detached from the photographing units of fundus cameras to capture images with a lens for a general-use single-lens reflex camera. The digital cameras are, however, sensitive to infrared rays, and may capture images operator does not intend or expect.